DE19510026A1 - Sulphonated aromatic polyether-ketone used for membrane prodn., etc. - Google Patents

Abstract

Sulphonated aromatic polyether-ketones (PEK) contg. units of formula -Ar-Op-Ar-(CO-Ar')x-O-Arm-CO-Ar'y-O-Arn-CO- (II) are claimed, in which 1-100% of the -O-phenylene-CO- units are substd. with a SO3M gp., sulphonated and unsulphonated -O-phenylene-CO- gps., and sulphonated and unsulphonated -O-phenylene-O- gps. in any sequence. In (II), Ar = p- and/or m-phenylene (p- and/or m-Phe); Ar' = phenylene, naphthylene, biphenylene, anthrylene or other arylene; M = H, NR4<+> (R = H or 1-4C alkyl) or a metal, pref. an alkali(ne earth) metal or sub-Gp. 8 metal; x, n and m = 0 or 1; y = 0, 1, 2 or 3; and p = 1, 2, 3 or 4. Also claimed are: (i) a process for the prodn. of (II); (ii) a polymeric electrolyte soln. contg. (II); and (iii) a film with a thickness of 5 mu m to 1 mm contg. (II).

Description

The invention relates to polymer electrolytes made from a sulfonated aromatic polyether ketone, a process for their preparation, Use of these polymer electrolytes and solutions of these Polymer electrolytes and use thereof.

Sulfonated polyether ketones are cation-ion exchangers. They are useful as membrane materials, e.g. B. for ultrafiltration, desalination and Removal of microorganisms, since in many cases they are also present in the presence of Water are mechanically resistant. Sulfonated polyether ketones are proton and cation-conducting materials that are useful for electrodialysis or as Part of electrochemical cells.

Starting materials are aromatic polyether ketones as in the general Formula (I) given

[Ar-O-] _q -Ar - [[CO-Ar′-] _r -O-Ar] _s - [CO-Ar′-] _t - [O-Ar-] _u -CO-] (I)

in which
Ar is a phenylene ring with p and / or m bonds,
Ar ′ is a phenylene, naphthylene, biphenylene, anthrylene or other divalent aromatic unit,
r, u and s are independently 0 or 1,
t 0, 1, 2 or 3,
q 1, 2, 3 or 4
mean. The polymer with q = 1, r = 0, s = 1, t = 0, u = 0 is commercially available under the name Victrex. The polymer with q = 1, s = 0, t = 2, u = 1 is commercially available under the name Ultrapek.

Polyether ketones are easily accessible. In principle, they can be Build up electrophilic polycondensation according to Friedel-Crafts, whereby a corresponding aromatic bisacid dihalide with an aromatic ether is implemented. This possibility is e.g. In U.S. 3,065,205, GB 971,227, US-3,441,538, GB-1,387,303, WO 84-03 891 and in the article of Iwakura, Y., Uno, K. and Tahiguchi, T.J., Polym. Sci., Pat. A-1, 6, 3345 (1968). In addition, the ether ketones can be nucleophilic gain aromatic substitution. For this, a corresponding aromatic bisdiol reacted with an aromatic bishalogen ketone, such as it z. B. in: R.A., Clendinning, A.G. Farnham, W.F. Hall, R.N. Johnson and C.N. Merriam, J. Polym. Sci. A1, 5, 2375, (1967), GB-1 177 183, GB-1 141 421, EP-0 001 879, US 4 108 837, US 4 175 175, T.E. Attwood, FROM. Newton, J.B. Rose, Br. Polym. Journ., 4, 391, (1972); T.E. Attwood, P.C. Dawson, J.L. Freemann, L.R.J. Hoy, J.B. Rose, P.A. Staniland, polymer, 22, 1096, (1981).

The production of sulfonated polyether ketones from some of these Polyether ketones are described in EP-A-008 895, EP-A-041 780 and EP-A-575 807.

According to EP-A-008 895, the polymer to be sulfonated is at room temperature suspended in 98% by weight sulfuric acid. The dissolving process and the Sulfonation take place simultaneously, gradually becoming a very viscous solution is obtained. This solution is either left to itself or at diluted at the same temperature with sulfuric acid of the same concentration. The The reaction is very slow. After 10 weeks, only about 90% were sulfonatable phenylene units sulfonated. In the used The number ratio of ether bridges to CO bridges was polyether ketones about 2: 1. According to EP-A-008 895 only under these conditions Sulfonated O-phenylene-O units.  

According to the method according to EP-A-041 780 at elevated temperature aromatic polyether ketones, which are copolymers, sulfonated. Just a part of the monomer units (A) is amenable to sulfonation, while others Monomer units (B) are not sulfonated. By the ratio A / B lets control the degree of sulfonation. However, they remain here Reaction conditions during the dissolving process and thereafter unchanged. Corresponding homopolymers (A) would be used under the specified conditions be sulfonated too high and thus lead to water-soluble compounds. There here the sulfonation already during the dissolving process of the polymer takes place, it is difficult to control the degree of sulfonation and low to obtain sulfonated products. In the process according to EP-A-041 780 are also only O-phenylene-O units under these conditions sulfonated.

In the process disclosed in EP-A-575 807, the one to be sulfonated Polymer at room temperature in sulfuric acid from 94 to 97% by weight suspended. The dissolution process and partial sulfonation of the polymer run off simultaneously, gradually obtaining a viscous solution. The A sulfonating agent is added to the solution until the Sulfuric acid concentration is 98 to 99.9 wt .-%. The solution remains until the desired degree of sulfonation is reached and is then worked up. Under these conditions, only O-phenylene-O units are sulfonated, while O-phenylene-CO units are not attacked. This is also from Daoust et al. (Polymer, Vol. 35 (25), 5491-5497 (1994)), the Sulfonation process is limited to one sulfonic acid group per Repetition unit and to one of the four equivalent positions of that of two Phenylene rings surrounding ether units. The other two phenylene rings are so strongly deactivated by the neighboring ketone unit according to Daoust, that no sulfonation takes place here.  

In the sulfonation of polyether ketones using Chlorosulfonic acid or a SO₃ / triethyl phosphate complex becomes a high degree of crosslinking and decomposition of the polymer main chain observed (Marvel et al., Journal of Polymer Science, Polymer Chem. Edition, vol. 23, 2205-2223, (1985) and Bishop et. al., Macromolecules, vol. 18, 86-93 (1985)).

In the methods known in the prior art, the used polyether ketones only sulfonated O-phenylene-O units, while O-phenylene-CO units and CO-phenylene-CO units not or only too be sulfonated to a negligible proportion or when used More drastic conditions result in networking or destruction of the Polymer backbone. Polymers that do not have O-phenylene-O units cannot be sulfonated to a significant extent. The in use Products obtained under harder reaction conditions are conventional Solvents are insoluble and can therefore not or only with difficulty with solution to be processed further.

According to the state of the art, it was not to be expected that Allow O-phenylene-CO units to sulfonate in a polyether ketone. Likewise According to the prior art, it was not to be expected that this would be the case Let sulfonated products dissolve in conventional solvents. After this State of the art was considered impossible, gentle in a polyether ketone To sulfonate phenylene rings that are directly adjacent to a keto group, if crosslinking or degradation of the polymer main chain does not occur at the same time.

The object of the present invention is therefore a gentle and controllable process for the sulfonation of polyether ketones to provide general formula (I), with this method in addition to Let O-phenylene-O units also sulfonate O-phenylene-CO units and to obtain new sulfonated polyether ketones in this way. Another task is to make solutions of these polymers.  

Surprisingly, it has now been found that the invention Polymers well and controllable in addition to the O-phenylene-O units Allow O-phenylene-CO units to sulfonate, the products obtained starting are even soluble to a certain degree of sulfonation.

The present invention therefore relates to a sulfonated aromatic Polyether ketone of the general formula (II)

[[Ar-O-] _p -Ar - [[CO-Ar′-] _x -O-Ar] _m - [CO-Ar′-] _y - [O-Ar-] _n -CO-] (II)

in which 1% to 100% of the O-phenylene-CO units are substituted with an SO₃H group and here sulfonated and unsulfonated O-phenylene-CO units and sulfonated and unsulfonated O-phenylene-O units are in any order to one another can
and where
Ar is a phenylene ring with p and / or m bonds,
Ar ′ is a phenylene, naphthylene, biphenylene, anthrylene or other divalent aromatic unit,
x, n and m independently of one another 0 or 1,
y 0, 1, 2 or 3,
p 1, 2, 3 or 4
mean.

The present invention also relates to a method for producing this sulfonated polyether ketones of the general formula (II), Polymer electrolyte solutions containing polymers of the general formula (II) and the use of such polymer electrolyte solutions.

With the aid of the method according to the invention, aromatic Polyether ketones of the general formula (I) also on the O-phenylene-CO units are sulfonated.  

In accordance with the published literature, it is found that the Sulfonation is preferred on the O-phenylene-O units of the polyether ketones takes place. Surprisingly, it was found that with the help of process according to the invention also at higher degrees of sulfonation significant proportion of the O-phenylene-CO units is sulfonated.

The process is characterized in that the aromatic Dissolves polyether ketone in sulfuric acid from 94 to 98 wt .-%, the obtained solution with a sulfonating agent until the Sulfuric acid concentration 98 to 100 wt .-% or until Oleum concentration 0.01 to 15 wt .-% SO₃ is, a suitable Setting the reaction temperature and working up the reaction mixture as soon as the desired degree of sulfonation has been reached.

Preferably, the aromatic polyether ketone is submerged in sulfuric acid gentle conditions solved, d. H. under conditions where a Sulfonation is largely suppressed, or not yet Sulfonation is coming. The concentration is preferably that for dissolution used sulfuric acid 94 to 97 wt .-%. The dissolving temperature is like this chosen as low as possible to prevent the onset of the sulfonation reaction largely avoided at this stage. In general, the Dissolving temperature between 10 and 80 ° C, in particular between 20 and 70 ° C, preferably between 30 to 60 ° C.

In particular, all divalent divalent aromatic radicals exist Ar and Ar 'of the polymer to be sulfonated from phenylene, preferably from 1,4-phenylene.

Homopolymers of the general formulas (III) and (IV) are preferred used. The sulfonation process described allows under controlled Conditions also the sulfonation of polyether ketones O-phenylene-CO units.  

In a further preferred embodiment, this is to be sulfonated Polyether ketone is a copolymer of at least two different units of the Formulas (III), (IV) and (V).

For the homopolymer of formula (III), for example, according to Dissolve at a maximum of 80 ° C and after 5 h at room temperature in Sulfuric acid of 95 or 97 wt% degrees of sulfonation less than 14 mol% based on a repeat unit was observed.

For the homopolymer of formula (IV) z. B. after a release process maximum 80 ° C and after 24 h at room temperature in sulfuric acid from 95 or 97% by weight and at a sulfonation temperature in the range of 30 to 90 ° C degrees of sulfonation of about 25 mol% based on Repeat unit observed.  

Preferred are dissolving conditions that lead to a maximum degree of sulfonation 35 mol% based on a repeat unit. During the Solving process, sulfonation of the main chain is largely suppressed. Our own investigations have shown that none during the dissolving process Degradation occurs.

As a sulfonating agent that increases the concentration of sulfuric acid and is used for sulfonation, preferably sulfuric acid, fuming Sulfuric acid, oleum, chlorosulfonic acid and sulfur trioxide are used.

Depending on the ratio of the O-phenylene-O units to the O-phenylene-CO units and depending on the CO-phenylene-CO units this changes from the sequence of these units along the main polymer chain Sulphonation behavior of the polyether ketones. Changes in the electron balance of the phenylene rings directly influence their sulfonation behavior. But also Side reactions are caused by changes in the electron balance of the Phenylene rings affected: The combination of the reaction parameters, the Sulfuric acid concentration, the reaction temperature and the reaction time, determines to what extent O-phenylene-O units and O-phenylene- CO units are sulfonated and to what extent cross-linking Sulfone groups or main chain degradation occur.

For each polyether ketone, other combinations are therefore the Reaction parameters ideal, on the one hand, a high proportion of sulfonated Obtain O-phenylene-CO units and on the other hand Crosslinking reactions and chain degradation at the lowest possible level to keep. The inventive method is characterized in that selects the appropriate combination of parameters in order to To ensure the most favorable course of the sulfonation reaction.  

After the dissolving process, the concentration of sulfuric acid, e.g. B. by Addition of oleum until the sulfuric acid concentration increases from 98 to 100 wt .-% or until the oleum concentration is 0.01 to 15 wt .-% SO₃, in particular up to the sulfuric acid concentration of 98.5 to 100% by weight or up to the oleum concentration is 0.01 to 5 wt .-% SO₃, preferably until the Sulfuric acid concentration 98.5 to 100 wt .-% or until the Oleum concentration is 0.01 to 1 wt .-% SO₃.

The reaction temperature in the actual sulfonation can be higher or higher are lower than in the dissolving process. In general, sulfonation Temperatures in the range from 10 to 100 ° C, in particular 30 to 95 ° C, particularly preferably 50 to 90 ° C. Both a temperature increase as well an extension of the reaction time causes an increase in Degree of sulfonation of the polymer. In particular, the temperature is Solution after adding the sulfonating agent at least 30 ° C. Typical Response times range from 45 minutes to 24 hours, preferably 1 and 8 hours, particularly preferably in the range of 1 to 4 hours. As soon as the desired degree of sulfonation is reached, the reaction is stopped and the polymer e.g. B. precipitated in an aqueous medium, isolated and dried.

Studies have shown that during the sulfonation reaction only in Minor degradation of the main polymer chain occurs. Possibly existing CO-phenylene-CO units of the aromatic used Polyether ketones are not used in the process of the invention sulfonated.

The advantage of sulfonated O-phenylene-CO units compared to sulfonated O-phenylene-O units in conventional polymers is below other in the better hydrolytic stability of the SO₃H groups. In aqueous environment and at elevated temperatures can desulfonate the sulfonated polyether ketones occur. It is known that the measure of hydrolytic desulfonation from the electron wealth of aromatic  Rings depends.

It is when using sulfonated polymers in the aqueous medium indispensable that the properties of the sulfonated polymer remain constant. In such applications it is therefore advantageous to use a sulfonated one To use polyether ketone, the desulfonation not or only to one to a limited extent. A polymer whose sulfonic acid groups become one are localized as high as possible to O-phenylene-CO units therefore particularly suitable in such cases.

The process described results in sulfonation products that start from one certain degree of sulfonation in conventional solvents, such as. B. NMP or DMSO. The manufactured in this way In a preferred embodiment, polymer electrolyte solutions contain at least 1% by weight of polyether ketones of the formula (II) and as the main constituent aprotic dipolar solvents, such as. B. N-methylpyrrolidone (NMP) or Dimethyl sulfoxide (DMSO).

Depending on the intended use of the polymer electrolyte solution, it can optionally a further unsulfonated polymer or small proportions of auxiliary substances included.

The polymer electrolyte solutions according to the invention are particularly suitable for Manufacture of asymmetrical membranes, for example for the nano, ultra or microfiltration and for the production of dense films with a thickness in Range from 5 µm to 1 mm.

A particularly important role is played by the invention Polymer electrolyte solutions in the manufacture of a particularly intense Contact between two polymer electrolyte surfaces. A porous or rough surface can e.g. B. after contacting the solution with a Precipitating agents can be achieved.  

Examples

In a four-neck stirrer with dropping funnel and oil bath, 96% was Concentrated sulfuric acid and various polyether ketones general formula (I) solved. Then oleum (content 20 wt .-% SO₃) titrated until a sulfonating mixture was reached with Sulfuric acid concentrations of 98.5 to 100 wt .-% or Oleum concentrations of 0.1 to 0.7 wt .-% SO₃. Then the Mixture brought to reaction temperature for optimal and controlled To ensure sulfonation. After reaching the desired one Degree of sulfonation, the reaction was stopped and the product isolated. The Characterization of the product takes place by means of viscometry, 13 C NMR spectroscopy and elemental analysis.

The experiments in Table 1 were carried out with a homopolymer of the general formula (III). The experiments in Table 2 were carried out with a homopolymer of the general formula (IV). The following abbreviations are used in the tables:
NR trial number
LT release temperature in ° C
PK polymer concentration in% by weight
RK reaction concentration of oleum in wt .-% SO₃
RC reaction concentration of sulfuric acid in wt .-% H₂SO₄
RT reaction temperature in ° C (sulfonation temperature)
RZ response time in min
SG degree of sulfonation in mol% based on a repeat unit
SEE Degree of sulfonation of the O-phenylene-O units in mol% based on a repeat unit
SEK Degree of sulfonation of the O-phenylene-CO units in mol% based on a repeat unit
IV inherent viscosity in dl / g (measured in conc. H₂SO₄ at 25 ° C)

Table 1

Table 2

Claims (23)

1. Sulfonated aromatic polyether ketone of the general formula (II) [Ar-O-] _p -Ar - [[CO-Ar′-] _x -O-Ar] _m - [CO-Ar′-] _y - [O-Ar -] _n -CO-] (II) in which 1% to 100% of the O-phenylene-CO units are substituted with a SO₃H group and here sulfonated and unsulfonated O-phenylene-CO units and sulfonated and unsulfonated O- Phenylene O units can be in any order to one another,
and where
Ar is a phenylene ring with p and / or m bonds,
Ar ′ is a phenylene, naphthylene, biphenylene, anthrylene or other divalent aromatic unit,
x, n and m independently of one another 0 or 1,
y 0, 1, 2 or 3,
p 1, 2, 3 or 4
mean and the combination p = 1, m = 0, y = 2, n = 1 is excluded. 2. Process for the preparation of a polyether ketone of the general formula (II), where Ar, Ar ', x, n, m, y and p have the meaning given in claim 1, by dissolving a polyether ketone of the general formula (I) wherein Ar, Ar ′, q, r, s, t and u have the following meanings: [Ar-O-] _q -Ar - [[CO-Ar′-] _r -O-Ar] _s - [CO-Ar′-] _t - [O-Ar] _u -CO-] (I) Ar is a phenylene ring with p and / or m bonds,
Ar ′ is a phenylene, naphthylene, biphenylene, anthrylene or other divalent aromatic unit,
r, u and s are independently 0 or 1,
t is 0, 1, 2 or 3 and
q is 1, 2, 3 or 4
in sulfuric acid from 94 to 97% by weight, add a sulfonating agent to the solution obtained at a suitable temperature and work up the reaction mixture thus obtained as soon as the desired degree of sulfonation has been reached. 3. The method according to claim 2, characterized in that the Dissolving temperature is in the range of 10 to 80 ° C. 4. The method according to claim 2, characterized in that the Sulfonation temperature is in the range of 10 to 100 ° C. 5. The method according to claim 2, characterized in that after the addition of the sulfonating agent the temperature of the solution at least 30 ° C. is. 6. The method according to claim 2, characterized in that as Sulfonating agent sulfuric acid, fuming sulfuric acid, oleum, Chlorosulfonic acid, sulfur trioxide or mixtures of these compounds be used. 7. The method according to claim 2, characterized in that one in Sulfuric acid dissolved polyether ketone mixed with oleum until the Sulfuric acid concentration 98 to 100 wt .-% or the Oleum concentration is 0.01 to 15 wt .-% SO₃. 8. The method according to claim 2, characterized in that the rest Ar ' represents phenylene.   9. The method according to at least one of claims 2 to 7, characterized characterized in that an aromatic polyether ketone is used, the represents a copolymer consisting of at least two different Units of the formulas (III), (IV) and (V) is constructed. 10. The method according to at least one of claims 2 to 7, characterized characterized in that mixtures of different aromatic Uses polyether ketones in which at least one of units of Formulas (III), (IV) or (V) is constructed. 11. The method according to at least one of claims 2 to 10, characterized characterized in that an aromatic polyether ketone is used, whose non-sulfonatable units are CO-phenylene-CO units. 12. The method according to claim 2, characterized in that the Polyether ketone has the general formula (III) in sulfuric acid of 95 up to 97% by weight at a maximum of 80 ° C and in sulfuric acid from 95 to 99 wt .-% is sulfonated at temperatures of 10 to 80 ° C. 13. The method according to claim 2, characterized in that the Polyetherketone has the general formula (IV), in sulfuric acid 95 to 97 wt .-% is dissolved at a maximum of 80 ° C and in sulfuric acid from 95 to 97 wt .-% sulfonated at temperatures from 30 to 90 ° C. becomes. 14. Process for the preparation of a sulfonated polyether ketone by dissolution of the polyether ketone in sulfuric acid from 94 to 97% by weight, Sulphonation of the polyether ketone in sulfuric acid, smoking Sulfuric acid, oleum, chlorosulfonic acid or mixtures thereof and Working up the reaction batch as soon as the desired one Degree of sulfonation is reached, characterized in that 1 to 100% the O-phenylene-CO units are substituted with a SO₃H group.   15. Polymer electrolyte solution containing a sulfonated aromatic A polyether ketone according to claim 1. 16. Polymer electrolyte solution according to claim 15, characterized in that they contain at least 1% by weight of polyether ketones of the formula (II). 17. Polymer electrolyte solution according to claim 15, characterized in that they as the main component of aprotic dipolar solvents, such as. B. N-methylpyrrolidone or dimethyl sulfoxide. 18. Polymer electrolyte solution according to claim 15, characterized in that they another, optionally unsulfonated polymer and optionally contains small amounts of auxiliary substances. 19. Use of the polymer electrolyte solution according to claims 15 to 18 for Manufacture of asymmetric membranes, for example for the nano, Ultra or microfiltration. 20. Use of the polymer electrolyte solution according to claims 15 to 18 for Production of dense films. 21. Use of the polymer electrolyte solution according to claims 15 to 18 for To achieve particularly intensive contact between two Polymer electrolyte surfaces. 22. Use of the polymer electrolyte solution according to claims 15 to 18 Reaching a porous or rough surface after contacting the Solution with a precipitant. 23. Polymer electrolyte according to claims 15 or 18 in the form of films with a thickness of 5 µm to 1 mm.